Battery-operated screwdriver

ABSTRACT

A battery-operated screwdriver, having a housing ( 12, 18 ) with a handle ( 14 ), in particular bent at an angle like a pistol grip, with a preferably fixedly installed rechargeable battery ( 40 ), and with charge contact tongues ( 37 ) for charging the battery ( 40 ) on a charger shell ( 22 ), is always ready for use and available by quick, simple access to the tool insert and screwdriver bit, because its battery ( 40 ) is designed as a lithium ion cell (Li ion cell) and can be placed in a chronologically undefined way, particularly in intervals between uses, on a charger shell ( 22 ), and the charging mode can be produced automatically, and the charger shell ( 22 ) has a detachably securable, magazinelike bit holder ( 99 ), with a plurality of compartments into which screwdriver bits ( 20 ) can be inserted.

PRIOR ART

The present invention is based on a battery-operated screwdriver asgenerically defined by the preamble to claim 1.

Battery-operated screwdrivers are already available in the 2.4V to 3.6Vpower class, as known for instance from European Patent Disclosure EP 1066 930. They usually have NiCd cells as energy-storing means, an ON/OFFswitch with a short switch button, and without continuously variablespeed governing they have both a switch for switchover fromcounterclockwise to clockwise operation, a gear, in particular aplanetary gear, that steps the motor rpm down, and a motor with astandard diameter of 27.5 mm. There are rodlike and pistol-shapedversions as well as versions with a grip whose angle can be adjusted.For charging, these devices are either connected to a charger via aplug—in the manner of a cell phone or electric shaver—or are connectedto contacts via a mount into which the device is placed. The mounts canbe secured to a wall, for instance, to make handling for chargingsimpler.

For that purpose, the charging mode must be brought about for both thecharger and the electrical connection, but this does not happenautomatically after every use. As a result, the device is often notready for use precisely when it is needed, and the familiar memoryeffect for conventional NiCd batteries is another disadvantage. After acertain amount of time of not outputting power, NiCd batteriesdischarge, and so battery-operated screwdrivers equipped with themdischarge partially after a short time even when not used. If they areput in the charging mode when they are partially discharged, then aftercharging, because of the memory effect, only the difference from thenewly charged quantity—and hence reduced power—is available.

Another disadvantage of the known battery-operated screwdrivers is thelimited availability of screwdriver bits and various tool inserts.

ADVANTAGES OF THE INVENTION

The battery-operated screwdriver of the invention having thecharacteristics of claim 1 has the advantage that it can always bepicked up quickly and securely at the same place, with its fullavailable charged capacity, can be manufactured economically, and isextremely lightweight and handy.

Since there is almost no self-discharging in a lithium ion cell, thebattery-operated screwdriver is fully ready for use even after longperiods when it is not in use, and in such periods the battery-operatedscrewdriver can rest for an arbitrarily long time on the charger shellin the charging mode. The charger shell can be placed, standingsecurely, on a flat storage shelf and need not be secured or firmly heldwhen the battery-operated screwdriver is being removed. As a result, itcan always be removed quickly with only one hand; no plug has to beunplugged and no mount has to be removed. Moreover, it is automaticallyassured at all times that the battery-operated screwdriver is charged.

The charge contact tongues soldered to the circuit board protrudethrough openings in the lower end of the handle and in the chargingposition are contacted by counterpart contacts of the charger shell; noadditional cords or coupling plugs have to be actuated.

Depending on the direction of rotation of the motor, either a greenlight-emitting diode or LED—acting as a directional arrow pointingforward—or a red LED—as a directional arrow pointing to therear—soldered to the circuit board lights up. These LEDs are visiblethrough openings in the housing, which are covered by means of atransparent plastic part acting as a window. A further LED with arectangular frame, located between them, serves as a charge controllight or charge status indicator.

Because only a single long, slender lithium ion (Li ion) cell fixedlybuilt into the handle of the battery-operated screwdriver is used,instead of a plurality of 4/5 sub-C nickel-cadmium cells as arechargeable battery, an especially small circumference of the grip canbe achieved.

Two relatively large, hard spiral springs keep the ON/OFF buttonprestressed in its off position, and by fast opening and closing of thecontacts, given their increasingly high impedance over the service life,prevent their becoming fused to the contact plate.

The long ON/OFF button has a short actuation stroke, and as a result, itis especially easily actuatable at any arbitrary location in a way thatswitches on reliably. As a result—regardless of the actuationposition—only slight operator control forces are necessary, and thedevice can be switched on comfortably in virtually any position of theuser's hand. To improve the guidance of the ON/OFF button relative tothe housing, the ON/OFF button has two lateral guide tongues on itsinside, which are slidingly supported in a braced fashion in thehousing.

A further volumetric reduction of the battery-operated screwdriver isachieved by means of a compact construction of the gear and gearbox; thegear, as a planetary gear, is merely placed in the cylindrical gearboxand is prevented from falling out by an axial securing plate, and thegearbox itself, with internal toothing, also acts as a sun wheel.

Because the motor housing is composed of half shells slit in the middle,which embrace the gearbox from both sides in the manner of tongs withradially inward-protruding support tongues and keep it centered in theinstalled position, the gearbox can be connected precisely and securelyto the motor housing without separate fastening elements such as screwsor overlooking elements.

A further reduction in the weight and volume of the battery-operatedscrewdriver is achieved by dispensing with a chuck; by means of ahexagonal socket in the power takeoff shaft—fitting correspondingscrewdriver or drilling bits with a hexagonal shaft—these tools can bechanged quickly and simply.

The ON/OFF button and the switch for reducing the direction of rotationare designed such that on the one hand, when the ON/OFF button ispressed, the switch for reducing the direction of rotation is blockedand cannot be moved, and on the other, the ON/OFF button is blocked andcannot be pressed into the ON position when the switch for reducing thedirection of rotation is in the middle position, which is therecommended transport position.

The gearbox, the circuit board with the battery, motor, LEDs, andelectrical elements, as well as the switch button with contact plate andsprings, and the transparent plastic part are placed in a first halfshell; the second half shell is placed over it and closed with only fouridentical screws and is thus completely mounted and makes for a veryeconomical embodiment.

DRAWINGS

The invention is described in further detail below in terms of anexemplary embodiment in conjunction with the drawings.

FIG. 1 is a side view of the partly opened battery-operated screwdriver;

FIG. 2 is a front elevation view of the battery-operated screwdriver;

FIG. 3 is a side view of the battery-operated screwdriver, positioned ina charger shell;

FIG. 4 is an enlarged detail of the grip region of FIG. 1;

FIG. 5 is a top view on the charger shell with the battery-operatedscrewdriver in the charging position;

FIG. 6 is a view from behind of the charger shell with thebattery-operated screwdriver of FIG. 5;

FIG. 7 is a side view of the charger shell with the battery-operatedscrewdriver of FIG. 5, with a separate bit holder; and

FIG. 8 is a three-dimensional view of a variant of the charger shellseen from above.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

FIG. 1 shows a pistol-like battery-operated screwdriver 10 with a motorhousing 12 aligned with the screwing direction and with a handle 14 atan angle from the housing. The motor housing 12 with the handle 14 isformed of two half shells 16, 17, which can be put together, bracedtightly against one another, in a central plane 15. To that end, fourscrews extend through bores in the one half shell 17 into four screwdomes 19 in the other half shell 16 and hold the two firmly against oneanother.

An ON/OFF button 26 extends over the internal length of the handle 14,for actuating a switch, not identified by reference numeral. Because ofits particular length, the ON/OFF button 26 makes it easy to switch thebattery-operated screwdriver 10 on and off, even in positions in whichit is difficult to hold the battery-operated screwdriver. On its longsides, it is provided with support tongues 27 that enter the handle 14laterally and form a secure guide on corresponding counterpart faces ofthe half shells 16, 17 and enable a precise, play-free back-and-forthmotion.

The ON/OFF button 26 is braced elastically on the handle 14 via two hardcompression springs 28, 30, so that after the battery-operatedscrewdriver is switched on, the springs 28, 30 automatically return theON/OFF button 26, when it is let go, to its off position and stop themotion of the motor. The actuation stroke is limited by stops, notidentified by reference numeral, and with a length of 1 to 4 mm is veryshort and user-friendly.

For the entry of the ON/OFF button 26 into the motor housing 12, acorresponding opening 29, half of it located in each of the half shells16, 17, is provided which closely embraces the ON/OFF button 26 andguides it in shaftlike fashion. The ON/OFF button 26, on its face endtoward the handle 14, has one longitudinally protruding tongue each atthe top and bottom; these tongues protrude past the opening 29 and arebraced from inside on its edge and keep the ON/OFF button 26 bracedthereon in the off position and prevent its coming loose from thehousing 12.

The circuit board 36, in its lower region, has two symmetricalsymmetrically arranged charge contact tongues 37, which emerge from theplane of the circuit board 36 at a right angle and then each form largebearing faces bent outward at an angle on the end. These faces penetrateeach half shell 16, 17 symmetrically to the center plane 15 in the lowerend of the handle 14. At each place where they pass through it, they areembedded in “countersunk” fashion in a respective indentation inside thecontour of the handle and are accessible for the outward-protrudingcharge contacts 23 of the charger shell 22, which they fit over in thecharging state when resting on the charger shell 22 and are braced,securely contacted, because of their resilient arrangement.

The circuit board 36 also, approximately centrally and flat and near thesurface, has interference resistors and capacitors, not identified byreference numerals, and in the upper region it has the slider switch 38as well as two LEDs 57, 58 on the upper end for visually indicating thedirection of rotation.

The circuit board 36 is located with its long side parallel to thehandle 14 and with its short side crosswise to the center plane 15 andis clamped without play in groovelike recesses, not identified byreference numeral, in the two half shells 16, 17 in such a way that itis braced from the inside against the half shells 16, 17 and thus formsa reinforcing rib in the handle 14. Parallel to the circuit board 36, alithium ion cell with its known advantages as a battery 40 is placed inthe handle 14; in the installed state, it is embraced in tonglikefashion by the two half shells 16, 17 and positionally secured and isthus integrated into the strength structure of the housing 12. Thebattery 40 has a contact plate 42, 43, one at the top and one at thebottom, acting as a soldering lug and wired to the circuit board 36.

Above the ON/OFF button 26—in the nip between the angled handle 14 andthe motor housing 12—a slider sensor 39 is located transversely to thecenter plane 15 of the motor housing 12 and can be displaced back andforth through lateral openings, not identified by reference numeral, inthe half shells 16, 17. In forklike fashion, with an approximatelycentral recess identified by reference numeral, the slider sensor 39embraces a sliding device 41 of a boxlike slider switch 38 that is fixedin the upper region of the circuit board 36. The sliding device 41,placed on the slider switch 38, is adjustable via the slider sensor 39into the extreme left and extreme right side positions and into a middleposition.

A direct current motor 46 in the front region of the motor housing 12 isembraced in tonglike fashion by the half shells 16, 17 after they havebeen installed and is held in its working position without play, alignedparallel with the gearbox 18 placed in the motor housing 12. The motor46 has one rear and one front steplike motor collar 48, 49, from whichthe rear and front ends of the motor shaft 45 emerge. Via its front andrear motor collars 48, 49, the motor 46 is supported, centered in bracedfashion, in corresponding bearing-block-like ribs of the half shells 16,17. The front end 47 of the motor shaft 45 is provided with a flat faceor a dihedron, in particular reshaped, and in the installed positionwith this face or faces reaches into a correspondingly flattened recessof an input pinion 66 of the gear 65, designed as a planetary gear, thatis located in the gearbox 18. A force-locking coupling with a coarsedimensional tolerance and ease of installation is thus created, and themotor 46 with the gear 65 and the gearbox 18 can easily be put togetherand placed, in put-together form, into one of the half shells 16, 17 forfurther assembly.

On the face end, the two half shells 16, 17 embrace a gearbox 18,mounted as a separate cylindrical structural unit, in tonglike andform-locking fashion and firmly hold it without play. The gearbox, intwo axial, tonguelike, partly cylindrical extensions 60, extendingtoward the motor housing 12, has an annular housing groove 54, which isdefined by an annular bead 55. The annular bead 55 engages a fittingcounterpart annular bead 56 on the inside of the face end of the halfshells 16, 17 of the motor housing 12; counterpart annular beads 53 thatfit them on the half shells 16, 17 engage the annular housing groove 54of the gearbox 18 in form-locking fashion.

Counterpart extensions 61, angled transversely to the longitudinaldirection of the motor housing 12, reach without play into the twoasymmetrical recesses between the two extensions 60 of the gearbox 18and at the same time, in the manner of a bearing block, brace the motorcollar 58 of the motor 46 in centering fashion, so that the motor collaris likewise integrated into the strength structure of the motor housing12. No special fastening elements such as screws or the like are thenneeded. This makes the assembly easier, with a reduced number ofindividual parts.

At the top, the motor housing 12 has a transparent window 59 placed init, which extends longitudinally in the parting planes and is split inthe middle. Through three openings in the half shells 16, 17, itprovides a view to one blue and one red LED 57, 58, each associated withone direction of rotation of the motor shaft 45 and being aligned withit, as well as one charge control light located between the two LEDs.

A power takeoff spindle 20, designed on its face end as a hexagonalsocket 21 for receiving fitting standard bits, protrudes at the frontfrom the gearbox 18, which toward the front tapers to a rounded cone.The hexagonal socket 21 is provided with means that firmly hold thescrewdriver bit or drill bit, inserted into it, in captive fashion sothat for the axial removal of these bits, a certain resistance must beovercome by hand.

FIG. 2 shows the battery-operated screwdriver 10 from the front; beyondwhat FIG. 1 shows, the size ratios of the handle 14 to the length of theON/OFF button 26 become clear.

FIG. 3 shows a boxlike charger shell 22, whose outer contour, viewedfrom the side, corresponds to a triangle standing on its base. Theoblique faces are adapted to the pistol-shaped contour, facing towardthem when the battery-operated screwdriver 10 is placed on them, of thebattery-operated screwdriver 10 and are indented in groovelike fashion.The battery-operated screwdriver 10 can therefore enter with its insideinto fitting embedding means 25 (FIG. 8) for the handle 14 and for themotor housing 12 and gearbox 18 and can rest therein secured by its ownweight; the contacting between its charge contact tongues 38 and thecharge contacts 23 of the charger shell 22 is especially secure.

The charge contacts 23 protrude upward out of the contour of theembedding means 25 of the charger shell 23, so that when thebattery-operated screwdriver 10 is placed in the corresponding embeddingmeans 25 of the charger shell 22, it is braced by its own weight, viaits charge contact tongues 37, on the resilient charge contacts 23 (FIG.8). Solely by placing the battery-operated screwdriver 10 on theintended place of the charger shell 22, the charging state automaticallyensues, with an audible click, as a result of mechanically securecontacting, as long as the charger shell 22 is connected to the powergrid via its electric cord 24. To that end, the electric cord 24 emergesat the left, in the viewing direction, from the charger shell 22 andextends to the power connection or the power supply of the charger shell22.

In the rear region, associated with the handle 14 of thebattery-operated screwdriver 10, the charger shell 22 has a releasablyclipped-in bit holder 99. This bit holder has a plurality of insertionopenings 95 for receiving standard screwdriver bits with a hexagonalshaft in captive fashion. The charger shell also, on its top in front ofthe bit holder 99, has three further, fixed insertion openings 73 forscrewdriver or drill bits.

FIG. 4 shows an enlarged detail of the first half shell 16 with theindividual parts inserted as in FIG. 1; the design of the battery 40with the adjoining parts as well as of the circuit board 36 with theparts secured to it and of the ON/OFF button 26 and the charge contacttongues 37 is clearly visible.

FIG. 5 shows a view from the top on the battery-operated screwdriver 10,seated in the charging position in the charger shell 22; in the viewingdirection to the left next to the handle 14 and parallel to it, ared-colored bit holder 99 can be seen. For overlockable reception of thebit holder 99, the charger shell 22 has a groovelike indentation 98,which is undercut in some regions and is slightly narrower than the bitholder 99. Since the bit holder is of elastic material, it can easily bepositionally secured, snapping into the indentation 98, when pressedfirmly.

The indentation 98 is longer than the bit holder 99, so that once thebit holder 99 has been inserted in the indentation 98 the indentationremains free in a residual region 96 for being grasped from below or forremoval of the bit holder 99 using one finger.

Hexagonal bits 93 can be secured in captive fashion, held by forcelocking in spring-elastically constrictable compartments 95 in themagazine-like bit holder 99, virtually perpendicular to the outercontour of the oblique faces of the charger shell 22.

At the top rear center, the battery-operated screwdriver 10 has oneforward-pointing and one rear-pointing, arrow-shaped window 90, 92 each,beneath which an LED that indicates the direction of rotation isseated—as well as a rectangular window 91, located between them, beneathwhich a charge control light is seated.

FIG. 6 shows a view of the charger shell 22 obliquely from behind withthe battery-operated screwdriver 10 placed on it. The removable bitholder 99 with approximately ten compartments 95 for insertingscrewdriver bits as in FIG. 5 can be seen along with the three fixed bitinsertion openings 73 in the front region of the charger shell 22. Itcan be seen that the bit holder 99 is fitted flush into the outercontour of the upper region of the charger shell 22.

FIG. 7 shows a side view of the charger shell 22 with thebattery-operated screwdriver 10 placed on it, along with the bit holder99 shown to the left of it in the viewing direction and locatedseparately.

FIG. 8 shows a top view on the charger shell 22, looking toward theembedding means 25, which is subdivided into a handle bed 251 and agearbox bed 252, so that the battery-operated screwdriver 10 can beplaced flush and virtually without play, unambiguously and in foolprooffashion, in the charger shell 22 in such a way that it rests securely,and its charge contact tongues 37 (FIGS. 1, 2, 4) gain a secure contactwith the charge contacts 23 of the charger shell 22.

1. A battery-operated screwdriver, having a housing (12, 18) with ahandle (14), in particular bent at an angle like a pistol grip, with apreferably fixedly installed rechargeable battery (40), and with chargecontact tongues (37) for charging the battery (40) on a charger shell(22), characterized in that the battery-operated screwdriver (10) has abattery (40), which is designed as a lithium ion cell (Li ion cell) andcan be placed on a charger shell (22), and the charging mode can beproduced automatically; and that the charger shell (22) comprises atleast one detachably mounted bit holder (99) fir storing tool inserts,particularly screwdriver bits, of the battery-operated screwdriver (10)in captive fashion.
 2. The battery-operated screwdriver as recited inclaim 1, characterized in that in the charging mode, the handle (14)protrudes so far from the charger shell (22) that for removing thebattery-operated screwdriver (10) it can comfortably be grasped frombeneath and/or largely encircled with the hand.
 3. The battery-operatedscrewdriver as recited in claim 1, characterized in that the chargecontact tongues (37) protrude outward through lateral slots (35) in thelower end of the handle (14) on both sides of the parting plane (15) onthe side of the internal angle and lock in the charging mode onto chargecontacts (23) of the charger shell (22), without requiring that separatecords or coupling plugs be actuated.
 4. The battery-operated screwdriveras recited in claim 1, characterized in that the battery-operatedscrewdriver (10), in the charging mode, fits with the indentations (33)in its handle (14) over the resilient charge contacts (23)on the chargershell (22) and is thus secured in overlocking fashion againstunintentional release from the charger shell.
 5. The battery-operatedscrewdriver as recited in claim 1, characterized in that the chargershell (22) has embedding means (25, 251, 252) on its top side forreceiving the battery-operated screwdriver (10), which correspond to acopy of its internal angle outer surfaces that are enclosed by thehandle (14) and the motor housing (12) and the gearbox (18); and that atleast one of the embedding means (25, 251 252) extends at an angle ofless than 90° to the vertical.
 6. The battery-operated screwdriver asrecited in claim 1, characterized in that the handle (14) enters inwedgelike fashion only with its ON/OFF button (26) into the embeddingmeans (25, 251, 252) of the charger shell (22), and the handle (14)itself protrudes from the charger shell (22) and dips only minimallyinto the embedding means (25, 251, 252).
 7. The battery-operatedscrewdriver as recited in claim 1, characterized in that the chargershell (22) can be placed, standing securely, on a flat and in particularhorizontal storage shelf, without having to be secured and firmly heldwhen the battery-operated screwdriver (10) is removed.
 8. A chargershell for a battery-operated screwdriver (10) wherein the charger shellhas at least one, detachably, mountable bit holder (99), configured toreceive a plurality of bits (93), which, in operation, can be insertedin a manner secure against relative rotation, in communication with thebattery-operated screwdriver (10) and wherein: the battery-operatedscrewdriver has a housing (12, 18) with a handle (14), in particularbent at an angle like a pistol grip, with a preferably fixedly installedrechargeable lithium ion cell battery (40), and with charge contacttongues (37) for charging the battery (40) on the charger shell (22),and the battery (40), can be placed on the charger shell (22), and thecharging mode can be produced automatically.
 9. The charger shell asrecited in claim 8, characterized in that the bit holder (99) ismountable laterally on the charger shell (22) and in the process isfitted flush into the outer contour of the charger shell (22), in anoverlockable fashion.
 10. The charger shell as recited in claim 9,characterized in that the charger shell (22) has an elongatedindentation (98) for receiving the bit holder (99), which indentation islonger than the bit holder (99) and which, with the bit holder (99)inserted, forms a permanent opening (96) for grasping from below withthe finger for the sake of removing the bit holder (99).
 11. The chargershell as recited in claim 10, characterized in that the bit holder (99)is located parallel to the indentation for the handle region of thebattery-operated screwdriver (10).
 12. The charger shell as recited inclaim 11, characterized in that the bit holder (99) is kept in thesignal color red, and the charger shell (22) is kept in the color blackand/or dark green and/or dark blue.
 13. The charger shell as recited inclaim 12, characterized in that input pinions (73, 95) for the bits (93)are located extending perpendicular to the contour of the charger shell(22).
 14. The charger shell as recited in claim 13, characterized inthat the charger shell (22) has input pinions (73), disposed fixedly inits front region, for captively receiving screwdriver bits (93),particularly in one row parallel to the length of the bit holder (99).15. The battery-operated screwdriver as recited in claim 1, wherein thebit holder (99) is overlockably received in the charger shell (22). 16.The battery-operated screwdriver as recited in claim 1, wherein thecharger shell (22) comprises a groovelike indentation for receiving thebit holder (99).
 17. The battery-operated screwdriver as recited inclaim 1, wherein the bit holder (99) is made of an elastic material.